I have considered adding a 3.7v to 5v converter wired directly to the cells in a 11200mA/h battery pod, I am already using a B&M E-werk converter but in mountainous areas the relatively small cache battery would be drawn down pretty quickly and experience significant wear in my case. I would prefer having the N900 watching for undervolt but resetting maybe once every 60-300 seconds.
Like with the Qi thread there is a hardware solution but the software solution can be almost as good and probably easier.